Nail-driving device



p 27, 1966 K. B E. HANSEN 3,275,209

NAIF-DRIVING DEVICE Filed Oct. 10, 1963 5 Sheets-Sheet l INVENTOR I KERN BO'EJE EMANUEL HANSEN BY Gnu A Tram/It p 1966 K. B. E. HANSEN 3,275,209

NAIL-DRIVING DEVICE Filed Oct. 10, 1965 5 Sheets-Sheet 2 FIG. 6

INVENTOR 30 KEEN B'RJE EMANUEL HANs/V INVENTOB HANSEN A'rTaR/VEYS K. B. E. HANSEN NAIL-DRIVING DEVICE 3 Sheets-Sheet 3 E'WG. I2

Sept. 27, 1966 Filed Oct. 10, 1963 United States Patent 3,275,209 NAIL-DRIVING DEVICE Kern Biirje Emanuel Hansen, Myrsjovagen 8, Saltsjo Boo, Sweden Filed Oct. 10, 1963, Ser. No. 315,313 Claims priority, application Sweden, Oct. 23, 1962,

11,332/62; Apr. 29, 1963, 4,672/63 12 Claims. (Cl. 227-10) The present invention relates to a nail-driving device, comprising a mainly tubular cylinder housing with a cylindrical bore, one end of which terminates in a muzzle. The muzzle has a cylindrical bore the diameter of which corresponds to the largest outer diameter of the nail which is to be driven and is placed for this purpose in the muzzle. The bore of the cylinder is closed at its inner end by a wall having a hole, in which an explosive charge is to be placed. A handle, preferably of the pistol grip type, containing a driver pin for initiating said charge and a triggering device for the pin is arranged on the outer side of the wall closing the cylinder. A piston which can move in the bore of the cylinder coacts with a driver extending from the end facing the muzzle and is of such a length that when the piston bears against the wall having the through hole, the driver extends into the bore of the muzzle.

Nail-driving devices of the above-mentioned kind are previously known, but have the disadvantages of being very heavy, difiicult to take apart and of having a powerful recoil movement.

The purpose of the present invention is to eliminate the above-mentioned disadvantages, by creating a light naildriving device, which is easy to take apart, easy to load, and with which the operator does not feel any recoil movement.

The elimination of the feeling of recoil by the operator is achieved in that the cylinder housing in the device is subjected to a certain minimum pressure in the nail-driving direction by the operator, through the handle, and in that the piston in the cylinder housing is braked at the end of its movement, so that the braking force and said minimum pressure together compensate the pressure which arises through the initiation of the explosive charge. Further, the weight of the piston and driver should be as low as possible in relation to the weight of the other parts of the device.

According to the invention, said braking is achieved through air compression, which moreover involves the advantage that when a driving action has been completed, the air cushion presses the piston back to its starting position.

According to a preferred embodiment of the invention, the striker pin and the triggering device are made in such a way that they together form a mainly cylindrical unit, which can easily be inserted and removed through a cylindrical aperture in the handle. This unit is also very easy to take apart.

The present invention will be described in more detail in conjunction with the attached drawing, in which:

FIG. 1 shows a complete nail-driving device according to the invention illustrating the most essential parts of the device,

FIG. 2 shows the nail-driving device opened and ready for loading,

FIG. 3 also shows the nail-driving device opened in such a way that the protruding lug of the triggering device is visible,

FIG. 4 shows the device according to the last-mentioned figure in a section in which it is shown how the lug can be actuated so that the triggering device can be removed,

FIG. 5 shows a partly exploded view of the triggering device,

FIGS. 6, 7 and 8 show the device in diiferent working phases,

FIG. 9 shows the details of the triggering device,

FIGS. 10 and 11 show the gas flow conditions in the cylinder housing in different working phases, and

FIG. 12 shows a graph of the forces, in relation to time, which act upon the handle of the device.

In the figures, there is shown a cylinder housing 1 with a cylindrical bore 2. One end of the cylinder housing is closed by a muzzle 3, which has a cylindrical bore 4. Said bore has a diameter mainly corresponding to the diameter of the head of the nail which is to be driven. It should be obvious that the muzzle can be exchanged for other muzzles with different lengths and other diameters, depending upon the sizes of the nails which are to be driven. A nail 5 with its head 6 is shown to be inserted into the muzzle. In order to guide the front end of nail, a washer 7 is placed on it. At the inner end of the muzzle a sealing ring 8, preferably made of some plastic material, has been placed, as well as a ring 9 made of metal. A suitable plastic material is polyurethane, known and available in the market under the trademark Trekollam 4020. In the cylindrical bore 4, one end of a cylindrical driver 10 is inserted, the other end of which bolt is joined to a piston 11. The piston is provided with a circumferential groove 12, in which a sealing ring 13, preferably an O-ring, is placed. A cylindrical extension 14 of the plunger extends into a cylindrical hole 15 in a closing plug 16, which is screwed into the other end of the cylinder housing. The hole 15 has an extension 17, with a smaller diameter suitable to accommodate a cartridge 18, the flange 18a of which rests against the plane end surface of the closing plug. In a peripheral line round the cylinder housing 1 there are three holes 19, arranged at an angle of from each other. In addition to said holes, there are also three holes 20, arranged along a peripheral line at an angle of 120 from each other.

The piston 11 and the driver 10' may be made of magnetic material to facilitate retention of the nail in the muzzle.

The cylinder housing is encircled by a protective casing 21, which can be displaced along the cylinder housing. However, the displacement is limited to the direction towards the handle, owing to the closing plug 16 being provided with a flange 22, which functions as a stopping lug. The casing 21 is held against this stopping lug by a spring 23, one end of which bears against the cylinder housing 1 and the other end against the casing 21. The casing 21 is rotatably supported in a ring 24, and is retained in this ring with the aid of a screw 25 and a groove 26 in the casing 21. The ring, in turn, is rotatably supported in a trigger guard 29, which is fixed to the handle 30, by means of a stud 27 and a pin 28.

The end of the casing 21, which bears against the flange 22, has locking lugs 31, which engage in a corresponding groove 32 in the handle 30. In the handle there is a cylindrical hole 33 with a groove 34. In the groove, a cylindrical unit 35 which comprises the triggering device is inserted. Said unit has a transversal hole 36, in which a scar 37 is inserted, which actuates a sear spring 38. The bolt has a transversal hole 39 in which the front end of a firing pin 40 is inserted. In its hole 39, the sear 37 has a bearing surface 41, which blocks the firing pin 40. The scar 37 also has a lug 42, which is guided in the groove 34. The hole 39 has an extension 43 in the cylindrical unit 35. A spring 44 holds the cylindrical unit 35 against the closing plug 16. The firing pin 40 is hollow, and is open at the end facing the handle. In the hole of the pin there is a spring 45, the end of which rests against the bottom of the hole 33. The spring 45 biases the firing pin 40 into the direction of the closing plug 16. The pin 40 is provided with a groove 46, so that the pin with the aid of a screw 47 cannot leave the cylindrical unit 35. At the end facing the hole 33, the pin 40 has a flange 47A, guided in a sleeve 48, provided with a flange 49, at the end opposite the bottom of the hole 33.

In the trigger guard 29 there is a trigger 50 pivotal on a pin 51 in the handle. The trigger has a protrusion 52, which via a leaf spring 53 can actuate the lug 42 when the lug is in a position above the leaf spring or directly above the protrusion 52.

The hole 33 accommodates a sleeve 54, which is held in place by a screw 55.

The trigger guard 29 has a guiding member 56, which extends into the groove 34, which is shaped to permit insertion of the cylindrical unit 53 into the hole 33 in spite of the protrusion 52.

The above-mentioned nail-driving device functions in such a way that, before driving in a nail, it is broken up as shown in FIG. 2. In this position, the cartridge 18 is inserted into the hole 17 and the nail into the bore of the muzzle 3. The device is thereafter closed, as shown in FIG. 1. The casing 21 is then turned in the direction indicated by the arrow, which secures the locking lugs in the groove. The device is now loaded, as is further shown in FIG. 6. The nail to be used is preferably a steel nail. The muzzle is placed against the wall point at which the nail is to be driven in, as shown in FIG. 7. The material into which the nail is to be driven is usually concrete or iron. The operator now presses the handle and the casing 21 first toward the wall against the action of the spring 23 and then successively against the action of the springs 44 and 45, until the cylindrical unit comes to bear against the respective transverse end wall of hole 33, as is clearly shown in FIG. 7. In this position, the trigger 50 can actuate the lug 42, so that the slide 37 is moved upwards, which has the result that the blocking action of the slide on the firing pin 40 ceases. The firing pin, owing to the spring 45, will now strike the cartridge 18. Gas is formed in the bore 14, and presses the piston 11 forward with such a force that the driver 10 drives in the nail 5. The piston 11 is braked during the latter part of its movement, owing to the fact that, when the piston has passed the holes 19 and 20, air is compressed in the space formed between the piston and the ring 9. When the driving has been completed, the piston is moved back to its original position by said compressed air.

In FIGS. 10 and 11 it is shown how air and gases flow through the holes 19 and 20, and how said air compression takes place.

At the above-mentioned firing procedure, the operator does not feel any recoil whatsoever. This is due to the fact that, through the subsequent compression of said three springs 23, 44 and 45, the cylinder housing is subjected to a great force in the direction into which the nail is driven. The braking of the piston adds to this force. The sum of the first-mentioned composite force and of the peak of the braking force is to be equal to the maximum amplitude of the force exerted by the cartridge. In FIG. 12 this is clearly shown, the acting forces being indicated as a function of the time. The forces are plotted along the ordinate axis, and the time along the abscissa. The curve 57 indicates the force with which the operator presses against the handle and the casing. The curve 58 indicates the force which is obtained through the braking, and the curve 59 indicates the force which generated by the ignition of the cartridge.

It is also of importance that the unit which consists of the piston 11, the cylinder 14 and the bolt 10 has as low a weight as possible in relation to the rest of the device.

The nail-driving device as described is easy to disassemble and reassemble, which is extremely favorable from the point of view of servicing. In FIGS. 3 to 5 it is shown how easy it is to insert and to remove the triggering device with the firing pin.

It is also shown in the other figures how easy it is to remove the cylinder housing 1 from the casing 21. For this purpose, only the closing plug 16 need be screwed out. The muzzle 3 can readily be screwed off from the cylinder housing 1.

A nail-driving device according to the present invention has been manufactured, and when driving nails into both concrete and iron it has not produced any noticeable recoil. The complete device as manufactured weighed 1.5 kg. The striker bolt 10, the plunger 11 and the cylinder 14 weighed 35 grammes together. The diameter of the cylinder housing was 15 mm. and its length of bore was mm. The height of the piston 11 was 10 mm., and the length of the driver was 85 mm. and its diameter 7 mm. The cylindrical extension had a height of 10 mm. and a diameter of 8 mm. The hole 15 had a height of 11 mm. and a diameter adapted to the cylinder 14. The hole 17 above it had a diameter of 6 mm. The cartridges used were cartridges known in the market as Fiocchi cartridges for nail-driving guns, 6.6 mm., of the black and yell-ow types. The volume of the air which was compressed during the last part of the movement of the piston 11 at the beginning of the compression was 4.7 cm. The hole 19 had a diameter of 6 mm. and a distance of 35 mm. from the ring 9. The hole 20 had the same diameter, with a center distance of 47 mm. The force with which the cylinder part is held against the respective transverse end wall of the hole 33 is between 13 and 14 kg.

While the invention has been described in detail with respect to a certain now preferred example and embodiment of the invention, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A nail driving device comprising an outer housing and an inner housing encompassed by the outer housing, said inner housing being lengthwise displacea-ble in reference to the outer housing and having a lengthwise bore; a muzzle for receiving a nail to be driven at one end of the bore of said inner housing, said muzzle having an inner diameter substantially equal to the largest outer diameter of the nail; an end wall at the other end of said inner housing Ibore, said end wall having an aperture therethrough to define a chamber for receiving an explosive charge therein; a handle assembly pivotally mounted on said outer housing for pivoting the handle assembly into and out of abutment with the outside of said apertured end wall of said inner housing rbore, said handle assembly comprising a triggering assembly including a firing pin and a spring coacting with said pin for propelling the same into said chamber to detonate a charge inserted therein, spring loading means slidable in said handle assembly and controlled by the position of the inner housing in reference to the outer housing, said spring loading means being engaged with said apertured housing end wall for loading said firing pin spring by displacement of the inner housing toward said handle assembly, locking means coacting with said firing pin for locking the same against the action .of said spring, said locking means being displaceable in unison with said spring loading means, release means movable to a position for releasing said locking means, said release means being operable in a predetermined position of displacement thereof thereby freeing said firing pin for propulsion into said chamber by the action of said spring, a piston displaceable in said inner housing, a driver for driving a nail received in the muzzle, said driver being secured to said piston and extending therefrom toward the muzzle, the length of the driver being such that the driver protrudes into the muzzle bore with a close fit when the piston is positioned in the inner housing to abut against said apertured housing end wall, detonation of a charge received in said chamber generating a gas pressure propelling the piston from said abutting position toward the muzzle thereby causing the driver to drive the nail, said inner housing having intermediate the length of its bore at least one venting port permitting escape of air from the bore until the iston passes said port while being propelled toward the muzzle, the remaining part of travel of the piston in the direction toward the muzzle causing compression of the air in said housing bore ahead of the piston, the gas pressure generated by detonation of the charge being dissipated through said port, whereby the compressed air in said housing bore part brakes the piston and re-expansion of the compressed air returns the piston to said abutting position, a first re-ooil compensating spring means including a first coil spring disposed in the outer housing and encompassing the inner housing, said first coil spring urging the inner housing outwardly in reference to the handle assembly, a second re-coil compensating spring means including a second coil spring disposed within the handle assembly and urging said spring loading means for the firing pin spring into a position in which the firing pin spring is relaxed, said first and said second coil springs and said firing pin spring being axially aligned with said housing bore so that displacement of the inner housing deeper into the outer housing and toward the handle assembly through a predetermined distance effects loading of the two coil springs and the firing pin spring, displacement of the inner housing relative to the outer housing and toward the handle assembly loading said first and second coil springs and moving said spring loading means int-o the position loading the firing pin spring and said locking means into the position for release by said release means, the release of the energy stored in the two loaded coil springs upon detonation of the charge by releasing the firing pin and the braking force of the compressed air acting cumulative in the direction in which the nail is propelled by the driver and in opposition to the force of the gas pressure generated by the detonation of the charge thereby substantially neutralizing the re-.

coil force generated by said gas pressure.

2. A nail-driving device according to claim 1 wherein the weight of the plunger including the weight of the striker in relation to the weight of the remaining components of the device is approximately 1:30.

3. A nail-driving device according to claim 1 wherein said inner housing has in its wall a row of three circumferentially, uniformly spaced venting ports.

4. A nail-driving device according to claim 5 wherein said inner housing has in its wall a second row of several circumferentially spaced venting ports, said two rows being lengthwise spaced.

5. A nail-driving device according to claim 1 wherein a sealing ring made of flexible material is provided at the end of the muzzle facing said bore of the inner housing.

6. A nail-driving device according to claim 7 wherein a second sealing ring made of a rigid material is superimposed upon said first ring on the side thereof facing said bore of the housing.

7. A nail-driving device according to claim 1 wherein said plunger has a peripheral groove and a sealing ring is fitted in said groove.

8. A nail-driving device according to claim 1 wherein the piston and the nail-driving bolt are made of magnetic material.

9. A nail-driving device according to claim 1 wherein said piston is formed with an extension on its side facing said apertured end wall of the inner housing, said extension being insertable into said wall aperture.

10. A nail-driving device according to claim 9 wherein said aperture is set off within the thickness of the end wall to define two different diameters within the depth of the aperture, the set-off portion of the aperture adjacent to the housing bore having a diameter fitting said extension and the other set-off portion having a diameter fitting said explosive charge.

11. A nail-driving device according to claim 1 wherein one of said housings has an external lug at one end, said lug forming an abutment limiting displacement of the inner housing in reference to the outer housing.

12. A nail-driving device according to claim 1 wherein said locking means comprise a spring-loaded sear disposed within the handle assembly transversely movable in reference to the striker pin between a position blocking lengthwise displacement of the firing pin and a position releasing the pin for such movement, and a trigger hinged to the handle assembly and engageable with said sear to move the same from its blocking position into its release position upon actuation .of the trigger.

References Cited by the Examiner UNITED STATES PATENTS 2,765,464 10/ 1956 Weichold 144.5 3,050,732 8/1962 Termet 144.5 3,065,560 11/1962 Bumiller 2279 XR FOREIGN PATENTS 585,084 10/1959 Canada. 744,822 2/ 1956 Great Britain.

GRANVILLE Y. CUSTER, JR., Primary Examiner. 

1. A NAIL DRIVING DEVICE COMPRISING AN OUTER HOUSING AND AN INNER HOUSING ENCOMPASSED BY THE OUTER HOUSING, SAID INNER HOUSING BEING LENGTHWISE DISPLACEABLE IN REFERENCE TO THE OUTER HOUSING AND HAVING A LENGTHWISE BORE; A MUZZLE FOR RECEIVING A NAIL TO BE DRIVEN AT ONE END OF THE BORE OF SAID INNER HOUSING, SAID MUZZLE HAVING AN INNER DIAMETER SUBSTANTIALLY EQUAL TO THE LARGEST OUTER DIAMETER OF THE NAIL; AN END WALL AT THE OTHER END OF SAID INNER HOUSING BORE, SAID END WALL HAVING AN APERTURE THERETHROUGH TO DEFINE A CHAMBER FOR RECEIVING AN EXPLOSIVE CHARGE THEREIN; A HANDLE ASSEMBLY PIVOTALLY MOUNTED ON SAID OUTER HOUSING FOR PIVOTING THE HANDLE ASSEMBLY INTO AND OUT OF ABUTMENT WITH THE OUTSIDE OF SAID APERTURE END WALL OF SAID INNER HOUSING BORE, SAID HANDLE ASSEMBLY COMPRISING A TRIGGERING ASSEMBLY INCLUDING A FIRING PIN AND A SPRING COACTING WITH SAID PIN FOR PROPELLING THE SAME INTO SAID CHAMBER TO DETONATE A CHARGE INSERTED THEREIN, SPRING LOADING MEANS SLIDABLE IN SAID HANDLE ASSEMBLY AND CONTROLLED BY THE POSITION OF THE INNER HOUSING IN REFERENCE TO THE OUTER HOUSING, SAID SPRING LOADING MEANS BEING ENGAGED WITH SAID APERTURED HOUSING END WALL FOR LOADING SAID FIRING PIN SPRING BY DISPLACEMENT OF THE INNER HOUSING TOWARD SAID HANDLE ASSEMBLY, LOCKING MEANS COACTING WITH SAID FIRING PIN FOR LOCKING THE SAME AGAINST THE ACTION OF SAID SPRING, SAID LOCKING MEANS BEING DISPLACEABLE IN UNISON WITH SAID SPRING LOADING MEANS, RELEASE MEANS MOVABLE TO A POSITION FOR RELEASING SAID LOCKING MEANS, SAID RELEASE MEANS BEING OPERABLE IN A PREDETERMINED POSITION OF DISPLACEMENT THEREOF THEREBY FREEING SAID FIRING PIN FOR PROPULSION INTO SAID CHAMBER BY THE ACTION OF SAID SPRING, A PISTON DISPLACEABLE IN SAID INNER HOUSING, DRIVER FOR DRIVING A NAIL RECEIVED IN THE MUZZLE, SAID DRIVER BEING SECURED TO SAID PISTON AND EXTENDING THEREFROM TOWARD THE MUZZLE, THE LENGTH OF THE DRIER BEING SUCH THAT THE DRIVER PROTRUDES INTO THE MUZZLE BORE WITH A CLOSE FIT WHEN THE PISTON IS POSITIONED IN THE INNER HOUSING TO ABUT AGAINST SAID APERTURED HOUSING END WALL, DETONATION OF A CHARGE RECEIVED IN SAIC CHAMBER GENERATING A GAS PRESSURE PROPELLING THE PISTON FROM SAID ABUTTING POSITION TOWARD THE MUZZLE THEREBY CAUSING THE DRIVER TO DRIVE THE NAIL, SAID INNER HOUSING HAVING INTERMEDIATE THE LENGTH OF ITS BORE AT LEAST ONE VENTING PORT PERMITTING ESCAPE OF AIR FROM THE BORE UNTIL THE PISTON PASSES SAID PORT WHILE BEING PROPELLED TOWARD THE MUZZLE, THE REMAINING PART OF TRAVEL OF THE PISTON IN THE DIREC- 